This invention relates to systems for processing comestible products, examples of which are dairy products such as milk, cream, and ice cream mix and other liquid food products, e.g., citrus juices, fruit juices and soups, and can also include pharmaceuticals. The invention is more particularly concerned with systems for cleaning continuous-process processing equipment, e.g., fruit juice processors, milk pasteurizers, or the like, by flowing a caustic cleaning solution through the equipment to remove food particles that may have become deposited on the walls of the tanks, tubing, or other components. The invention is concerned with a technique for recovering the caustic solution by separating out the solids components that become entrained in the caustic solution, and then returning the clear caustic solution for re-use.
In the food processing industry, the preparation of milk, orange juice or similar liquid food products is typically carried out in a continuous process system, in which the product flows in from a supply or balance tank, and is subjected to heating, evaporation, and other processing in a closed loop or an open loop that is formed of tubes, tanks, and other equipment such as pumps, homogenizers, and the like. At the end of a product run, which may be continuous for twelve hours or more, the equipment is cleaned and sanitized for a successive product run. Cleaning is typically carried out by flowing a cleaning solution through the system, for a period of time long enough to remove product that has deposited and caked on the surfaces of the processing equipment. This is followed by a rinse of clean water, and then finally hot water or steam can be passed through the equipment to sterilize it.
In conventional practice, the cleaning solution is made up as an aqueous solution of a caustic material, such as potassium hydroxide (KOH). At the end of the caustic phase of the cleaning process, the caustic solution and any entrained solids are discharged to a drain, and the solution is considered waste and is not reused. Moreover, any of the solid particles removed by the caustic and entrained in the solution are also discharged, and have to be processed as waste. Unfortunately, the caustic material can be quite expensive in the volumes needed for a typical dairy processing plant or citrus juice processing plant, and so any success in recovering the caustic solution would result in a cost savings. Also, there is some nutritive value in the food particles that are carried in the caustic solution, but no attempt has been made to recover those for any purpose. In addition, the discharge of the caustic material into a municipal sewage treatment facility can raise the pH of the system considerably, and can affect the ability of the sewage treatment facility to process other water-borne waste.